AXIOM: advanced X-ray imaging of the magnetosphere
AXIOM: advanced X-ray imaging of the magnetosphere
复制标题
DOI：
10.1007/s10686-011-9239-0
复制
发表时间：
2011-07
影响因子：
3
通讯作者：
G. Branduardi‐Raymont;S. Sembay;J. Eastwood;D. Sibeck;T. Abbey;P. Brown;J. Carter;C. Carr;C. Forsyth;D. Kataria;S. Kemble;S. Milan;C. Owen;L. Peacocke;A. Read;A. Coates;M. Collier;S. Cowley;A. Fazakerley;G. Fraser;G. Jones;R. Lallement;M. Lester;F. Porter;T. Yeoman
中科院分区：
文献类型：
--
作者：
G. Branduardi‐Raymont;S. Sembay;J. Eastwood;D. Sibeck;T. Abbey;P. Brown;J. Carter;C. Carr;C. Forsyth;D. Kataria;S. Kemble;S. Milan;C. Owen;L. Peacocke;A. Read;A. Coates;M. Collier;S. Cowley;A. Fazakerley;G. Fraser;G. Jones;R. Lallement;M. Lester;F. Porter;T. Yeoman
行星等离子体和磁场环境可以用两种互补的方式进行研究——就地测量或遥感。前者在局部尺度上提供了关于等离子体行为、不稳定性和动力学的精确信息，后者提供了理解磁层等离子体与太阳风整体相互作用所必需的全局视图。地球磁层的某些部分已被遥感到，但大部分仍未被这种测量方法探测到。在这里，我们提出了一种采用远程x射线成像技术的新颖而更优雅的方法，由于最近在地球磁层附近发现了太阳风电荷交换x射线发射，这种方法现在成为可能。在这篇文章中，我们描述了一个适当设计和定位的x射线望远镜，在太阳风的同时原位测量的支持下，可以用来成像日侧磁层、磁鞘和弓激波，其时间和空间分辨率足以解决关于太阳风如何在全球层面上与地球磁层相互作用的几个关键问题。白天磁层边界的全球图像需要远在磁层之外的有利位置。我们的研究使我们提出了“AXIOM：先进的磁层x射线成像”，这是一个概念任务，使用织女星发射器和LISA探路者型推进模块将航天器放置在围绕地月L1点的利萨朱斯轨道上。模型有效载荷包括一个x射线宽场成像仪，能够成像和光谱，以及一个原位等离子体和磁场测量包。该套件包括一个质子- α传感器，用于测量太阳风的整体特性，一个离子成分分析仪，用于表征太阳风中引起电荷交换发射的次要离子种群，以及一个磁力计，用于测量太阳风磁场的强度和方向。我们还展示了模拟，证明了所提出的x射线望远镜设计如何能够以实现任务科学目标所需的灵敏度和节奏对白天磁层的预测发射进行成像。
Planetary plasma and magnetic field environments can be studied in two complementary ways—by in situ measurements, or by remote sensing. While the former provide precise information about plasma behaviour, instabilities and dynamics on local scales, the latter offers the global view necessary to understand the overall interaction of the magnetospheric plasma with the solar wind. Some parts of the Earth’s magnetosphere have been remotely sensed, but the majority remains unexplored by this type of measurements. Here we propose a novel and more elegant approach employing remote X-ray imaging techniques, which are now possible thanks to the relatively recent discovery of solar wind charge exchange X-ray emissions in the vicinity of the Earth’s magnetosphere. In this article we describe how an appropriately designed and located X-ray telescope, supported by simultaneous in situ measurements of the solar wind, can be used to image the dayside magnetosphere, magnetosheath and bow shock, with a temporal and spatial resolution sufficient to address several key outstanding questions concerning how the solar wind interacts with the Earth’s magnetosphere on a global level. Global images of the dayside magnetospheric boundaries require vantage points well outside the magnetosphere. Our studies have led us to propose ‘AXIOM: Advanced X-ray Imaging of the Magnetosphere’, a concept mission using a Vega launcher with a LISA Pathfinder-type Propulsion Module to place the spacecraft in a Lissajous orbit around the Earth–Moon L1 point. The model payload consists of an X-ray Wide Field Imager, capable of both imaging and spectroscopy, and an in situ plasma and magnetic field measurement package. This package comprises a Proton-Alpha Sensor, designed to measure the bulk properties of the solar wind, an Ion Composition Analyser, to characterise the minor ion populations in the solar wind that cause charge exchange emission, and a Magnetometer, designed to measure the strength and direction of the solar wind magnetic field. We also show simulations that demonstrate how the proposed X-ray telescope design is capable of imaging the predicted emission from the dayside magnetosphere with the sensitivity and cadence required to achieve the science goals of the mission.